LOS ANGELES - Los Angeles police detectives say they hope a 1987 tape recording may lead to a serial killer who has killed at least 11 women over two decades.

The tape is of a call made from a pay phone, the Los Angeles Times reports. A man, who refused to give his name, said he had seen a body dumped from the back of a van. He gave the license plate number, which proved to be a van owned by a nearby church.

Police found a body where the caller said it would be. But the trail went cold, although the van's engine was warm when police found it, because no one from the church could be identified as the killer.

The investigation has been a disjointed one because detectives only determined recently that all 11 killings were the work of one person. Different generations of detectives worked the killings, all of prostitutes, including the most recent one in 2007, the Times said.

Detectives plan to release the tape recording for the first time, hoping it will trigger someone's memory. They told the Times that the caller may have been giving them good information or it could have been the killer deliberately misleading the investigation.